This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project is designed to act as a holding and resource project for animals that have been infected with SIV or HIV that are no longer required on the original project. The animals will be maintained in an ABSL-2/3 facilities. They will be monitored clinically to help define the natural pathogenesis of the disease. The animals may be reassigned to other projects in experimental drug evaluations, pathogenesis studies, vaccine studies, or studies requiring immunosuppressed and/or SIV/HIV-viremic animals. Blood will be drawn every 2-3 months for viral isolation, serology, CBC, serum chemistry, and T- cell subset analysis.